Patent attributes
A method for fabricating a semiconductor device includes forming a doped polysilicon layer on a semiconductor substrate forming an oxide film for device isolation in a predetermined region of the doped polysilicon layer and the semiconductor substrate, forming an etch stop layer on the oxide film for device isolation and the doped polysilicon layer, etching a predetermined region of the etch stop layer, the doped polysilicon layer and the semiconductor substrate to form a trench defining a gate region, depositing a gate oxide film on the gate region, forming a gate electrode layer and a hard mask layer filling the trench, and polishing the gate electrode layer and the hard mask layer to expose the etch stop layer and to form a gate in the gate region.